Abstract
Silicon (Si) can reduce the severity of fungal diseases in field crops, but the mechanism by which Si protects plants from fungal diseases is not well understood. This study investigated the effect of potassium silicate on the growth of five soilborne phytopathogenic fungi in vitro. Results showed that the growth of four of the fungal isolates (Rhizoctonia solani, Pestalotiopsis clavispora, Fusarium oxysporum and Fusarium oxysporum f. sp. fragariae) was signficantly (P < 0.05) inhibited on potassium silicate amended PDA plates. However, when the pH of potassium silicate amended PDA was reduced so that it was equivalent to unamended PDA (control), there was no difference in fungal growth between the two treatments. This indicated that the inhibition of fungal growth on potassium silicate amended PDA was due to a pH effect. Our results imply that reductions in fungal disease after field plants are treated with low concentrations of Si are probably not due to fungistatic effects of Si, but rather due to other mechanisms such as Si acting as a physical barrier against pathogen penetration or Si-induced defense response in plants.
Zusammenfassung
Silizium (Si) kann die Befallsstärke pilzlicher Krankheitserreger in Feldfrüchten vermindern, aber der Wirkungsmechanismus von Si wurde bisher nur unzureichend geklärt. In dieser Studie wurde der Einfluss von Kaliumsilikat auf das Wachstum von fünf bodenbürtigen pflanzenpathofgenen Pilzen in vitro untersucht. Die Eregebnisse zeigten, dass das Wachstum von vier Pilzisolaten (Rhizoctonia solani, Pestalotiopsis clavispora, Fusarium. oxysporum and Fusarium. oxysporum f. sp. fragariae) auf PDA-Petrischalen in Gegenwart von Kaliumsilikat signifikant (P < 0.05) vermindert war. Sank dagegen der pH des PDA-Kaliumsilikat-Mediums auf den Wert der PDA-Kontrolle, unterschied sich das Pilzwachstum der beiden Varianten nicht. Dies deutet darauf hin, dass die Wachstumsbeeinträchtigung auf Kaliumsilikat-PDA auf einem pHEffekt beruht. Die Ergebnisse implizieren, dass die Hemmwirkung geringer Si-Konzentrationen auf Pilzkrankheiten von Feldfrüchten wahrscheinlich nicht auf einer fungistatischen Wirkung, sondern eher auf anderen Mechanismen wie der Wirkung als physikalische Penetrationsbarriere oder einer Auslösung pflanzlicher Abwehrmechanismen durch das Si beruht.
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Shen, GH., Xue, QH., Tang, M. et al. Inhibitory effects of potassium silicate on five soil-borne phytopathogenic fungi in vitro. J Plant Dis Prot 117, 180–184 (2010). https://doi.org/10.1007/BF03356358
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DOI: https://doi.org/10.1007/BF03356358